scholarly journals OVEN OR FIREPLACE? (EXPERIMENTAL FIRINGS OF THE VESSELS)

2015 ◽  
Vol 4 (3) ◽  
pp. 37-55
Author(s):  
Yelena Vitalievna Volkova
Keyword(s):  
High Temperature ◽  
Basic Knowledge ◽  
Maximum Temperature ◽  
Firing Process ◽  
Cow Dung ◽  
Natural Clay ◽  
Analytical Studies

The paper contains the results of the field experimental firings in fireplaces and in ovens made on the basis of Samara pottery experimental expedition (Dr N.P. Salugina is the leader of the expedition) in 2013. The author put forward two goals: one is to discover the basic knowledge on firing process with various kinds of fuel, and second is to find out the specific features to discern the vessels fired in fireplaces from the vessels fired in ovens. 20 vessels were prepared to the experiment. The first 10 pots were made of natural clay and the second 10 vessels were made of pottery paste (clay + grog + cow dung). Five simultaneous firings with various kinds of fuel were organized in fireplace and in oven. The author describes in detail the program, main steps, and maximum temperature of firings, the photos of the vessels, and the results of their analytical studies. After the experiments the author came to the next conclusions: firstly - there are absent the reliable features to distinguish the vessels fired in fireplace and in oven, secondly - there is one dependence between a kind pottery paste and a color of fired vessels and another relation between pottery paste and a degree of high-temperature baking of vessels.

scholarly journals Study on the Stability of the Electrical Connection of High-Temperature Pressure Sensor Based on the Piezoresistive Effect of P-Type SiC

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 216
Author(s):  
Yongwei Li ◽  
Ting Liang ◽  
Cheng Lei ◽  
Qiang Li ◽  
Zhiqiang Li ◽  
...  
Keyword(s):  
High Temperature ◽  
Pressure Sensor ◽  
Pressure Sensors ◽  
Extreme Environment ◽  
Maximum Temperature ◽  
Piezoresistive Effect ◽  
Electrical Connection ◽  
Contact Stability ◽  
The Stability ◽  
P Type

In this study, a preparation method for the high-temperature pressure sensor based on the piezoresistive effect of p-type SiC is presented. The varistor with a positive trapezoidal shape was designed and etched innovatively to improve the contact stability between the metal and SiC varistor. Additionally, the excellent ohmic contact was formed by annealing at 950 °C between Ni/Al/Ni/Au and p-type SiC with a doping concentration of 1018cm−3. The aging sensor was tested for varistors in the air of 25 °C–600 °C. The resistance value of the varistors initially decreased and then increased with the increase of temperature and reached the minimum at ~450 °C. It could be calculated that the varistors at ~100 °C exhibited the maximum temperature coefficient of resistance (TCR) of ~−0.35%/°C. The above results indicated that the sensor had a stable electrical connection in the air environment of ≤600 °C. Finally, the encapsulated sensor was subjected to pressure/depressure tests at room temperature. The test results revealed that the sensor output sensitivity was approximately 1.09 mV/V/bar, which is better than other SiC pressure sensors. This study has a great significance for the test of mechanical parameters under the extreme environment of 600 °C.

Study on the Thermo-Hydrodynamic of a Dry Gas Seal in Helium Circulator for High Temperature Gas-Cooled Reactor

2011 ◽  
Author(s):  
Jianshu Lin ◽  
Hong Wang
Keyword(s):  
High Temperature ◽  
Film Flow ◽  
Three Dimensional ◽  
Maximum Temperature ◽  
Analysis Method ◽  
Dry Gas Seal ◽  
Safety Requirements ◽  
Simulation Results ◽  
Gas Seals ◽  
High Temperature Gas

A comprehensive analysis method is proposed to resolve the problem of simulating a complex thermo-flow with two kinds of distinct characteristic length in the dry gas seal, and a conjugated simulation of the complicated heat transfer and the gas film flow is carried out by using the commercial CFD software CFX. By using the proposed method, a three dimensional of velocity and pressure field in the gas film flow and the temperature distribution within the sealing rings are investigated for three kinds of film thickness, respectively. A comparison of thermo-hydrodynamics of the dry gas seals is conducted between the sealed gas of air and helium. The latter one is used in a helium circulator for High Temperature Gas-cooled Reactor (HTGR). From comparisons and discussions of a series of simulation results, it will be found that the comprehensive proposal is effective and simulation results are reasonable, and the maximum temperature rise in the dry gas seal is within the acceptable range of HTGR safety requirements.

scholarly journals OPTIMIZATION OF INORGANIC COMPONENTS OF FIRE PROTECTIVE VARNISH FOR WOOD

2021 ◽  
pp. 123-132
Author(s):  
Yu. Tsapko ◽  
◽  
А. Tsapko ◽  
O. Bondarenko ◽  
V. Lomaha ◽  
...  
Keyword(s):  
High Temperature ◽  
Fire Retardant ◽  
Protective Layer ◽  
Combustion Products ◽  
Wood Products ◽  
Maximum Temperature ◽  
Protective Film ◽  
Insulating Layer ◽  
Combustible Gases ◽  
Material Studies

Abstract. The processes of creation of fire-retardant varnish for wood consisting of a mixture of inorganic and polymeric substances are investigated in the work. It is established that the optimization of the inorganic component leads to a directional ratio of mineral acids and urea capable of effective fire protection of the material. Studies have shown that at the initial temperature of gaseous combustion products T = 68 °C, when exposed to the radiation panel, the untreated sample ignited after 146 s, the flame spread over the entire surface, instead, the sample fire-protected varnish did not ignite, the maximum temperature was 105 °C. In this case, as evidenced by the results of heat resistance, there is a change in the structure of the protective film of the coating. The thickness of the protective layer increases due to the decomposition of the composition, which leads to inhibition of oxidation in the gas and condensed phase, change the direction of decomposition towards the formation of non-combustible gases and combustible coke residue, reduce material combustion and increase flammability index. The coating under the influence of high temperature promotes the formation of a heat-insulating layer of coke, which prevents burning and the passage of high temperature to the material, which is confirmed by the absence of the process of ignition of fire-retardant wood. Features of braking of process of ignition and distribution of a flame of the wood processed by a varnish which consist in several aspects are established. This is the formation of a heat-insulating layer of coke, which prevents burning and the passage of high temperatures to the material, which is confirmed by the absence of the process of ignition of fire-retardant reeds. This indicates the possibility of targeted control of high temperature transfer processes to organic material through the use of special coatings for wood products.

Advanced wire bonding for high reliability and high temperature applications

2016 ◽  
Vol 2016 (1) ◽  
pp. 000214-000218
Author(s):  
M. Guyenot ◽  
M. Reinold ◽  
Y. Maniar ◽  
M. Rittner
Keyword(s):  
High Temperature ◽  
Band Gap ◽  
Mechanical Performance ◽  
High Reliability ◽  
Calculation Model ◽  
Basic Knowledge ◽  
Thermal Cycles ◽  
White Band ◽  
The Impact ◽  
Mission Profile

Abstract The next generation of switches for power electronic will be based on white band gap (WBG) semiconductor GaN or SiC. This materials supports higher switching current and high frequency. White band gap semiconductors enables higher application temperature. Certainly, high temperature capability is also to discuss in combination with high number of thermal cycles. For a frame module concept shows these paper a comparison of different joining techniques with the focus on the reliability issue on wire and ribbon bonding. Beside to the 1000 passive thermal cycles from −40°C to +125°C there are active thermals cycles for technology qualification required [3]. Depending on the application and mission profile a high thermal cycling capability is necessary. For this reason, new high temperature joining techniques for die attach, e.g. Silver sintering or diffusion soldering, were developed in the recent past [4]. All of this new joining techniques focusing on higher electrical, thermal and thermo-mechanical performance of power modules. By using an optimized metallization system for the WBG the numbers of thermal cycles can be increased and the maximum operating temperature advanced up to 300°C. In these new temperature regions silicon semiconductors will be substituted by WBG semiconductors. The present work shows an active power cycling capability of different wire and ribbon bonds and the failure mechanism will be discussed. A calculation model explained the reliability for the different wire diameter and the impact of bonding materials. This reliability calculation explain the thermo-mechanical effects and based on materials and geometry data and is not optimized for evidence. Through these physical background understanding more than 1.000.000 thermal cycles with a 150 K temperature swing from +30°C to +180°C are now possible. These is a the basic knowledge for a design for reliability based on current, mission profile and reliability optimization for future high end applications with wire or ribbon bonding technique.

Diurnally Alternating Temperatures Stimulate Sprouting of Purple Nutsedge (Cyperus rotundus) Tubers

Weed Science ◽  
1996 ◽  
Vol 44 (1) ◽  
pp. 122-125 ◽  
Author(s):  
Joel E. Miles ◽  
Roy K. Nishimoto ◽  
Osamu Kawabata
Keyword(s):  
High Temperature ◽  
Cyperus Rotundus ◽  
Maximum Temperature ◽  
Temperature Cycle ◽  
Purple Nutsedge ◽  
Tuber Temperature ◽  
Tuber Sprouting ◽  
Alternating Temperature ◽  
Increasing Temperature ◽  
Temperature Responses

Experiments were conducted to determine the response of purple nutsedge tuber sprouting to diurnally alternating temperature. These experiments compared the response to alternating and constant temperatures and determined the effect of the amplitude of alternation and time of exposure to the maximum temperature. Tuber sprouting was more rapid and complete with alternating temperatures than with constant temperatures. Increasing temperature fluctuation from 0 to 6 C for 12 h daily linearly increased total tuber sprouting. As little as 30 min exposure to high temperature per day provided nearly the same level of sprouting as a 12 h alternating temperature cycle. This phenomenon should be considered when conducting studies to describe tuber temperature responses or when predicting tuber sprouting and emergence.

The influence of pasture distribution and temperature on habitat selection by feral pigs in a semi-arid environment

1998 ◽  
Vol 25 (5) ◽  
pp. 547 ◽  
Author(s):  
Nick Dexter
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Radio Telemetry ◽  
Arid Environment ◽  
Food Distribution ◽  
Maximum Temperature ◽  
Feral Pigs ◽  
North West ◽  
Hot Weather ◽  
Two Parameters

The two parameters believed to influence habitat utilisation by feral pigs and wild boar (Sus scrofa) are protection from high temperatures and distribution of food. However, whether there is an interaction between these parameters is unknown. To examine the influence of high temperature on habitat utilisation, the use of four rangeland habitats (shrubland, woodland, riverine woodland, and ephemeral swamps) by feral pigs in north-west New South Wales, Australia, was measured by radio-telemetry during and after a drought. In each habitat, protection from high temperature was indexed once by vegetation cover, at three strata, while over the course of the study, food distribution was indexed by estimating pasture biomass in each habitat. Riverine woodland provided the most shelter from high temperature, followed by woodland, shrubland and ephemeral swamps. On average, ephemeral swamps had the highest pasture biomass, followed by riverine woodland, shrubland and woodland. The amount of pasture in each habitat increased after the drought but changed at different rates. During autumn, spring and summer feral pigs preferred riverine woodland but in winter shrubland was preferred. Multivariate regression indicated that habitat utilisation was significantly influenced by pasture biomass in shrubland and mean maximum temperature in the study area. The results suggest that feral pigs are restricted by high temperatures to more shady habitats during hot weather but when the constraint of high temperature is relaxed they distribute themselves more according to the availability of food.

Miocene high-temperature leucogranite magmatism in the Himalayan orogen

2020 ◽  
Author(s):  
Peng Gao ◽  
Yong-Fei Zheng ◽  
Matthew Jason Mayne ◽  
Zi-Fu Zhao
Keyword(s):  
High Temperature ◽  
Partial Melting ◽  
Plate Boundary ◽  
Source Rocks ◽  
Eastern Himalaya ◽  
Maximum Temperature ◽  
Himalayan Orogen ◽  
Metasedimentary Rocks ◽  
Se Tibet ◽  
Zircon Thermometry

Himalayan leucogranites of Cenozoic age are generally attributed to partial melting of metasedimentary rocks at low temperatures of <770 °C. It is unknown what the spatial distribution and characteristics of high-temperature (>800 °C) leucogranites are in the Himalayan orogen. The present study reports the occurrence of such leucogranites in the collisional orogen. We use the Ti-in-zircon thermometry in combination with the thermodynamically calibrated relationships of T-aSiO2-aTiO2 to retrieve crystallization temperatures of Miocene (ca. 17 Ma) two-mica granites from Yalaxiangbo, in the eastern Himalaya, SE Tibet. The results give the maximum temperature as high as ∼850 °C for granite crystallization, providing a significant constraint on the nature of thermal sources. Phase equilibrium modeling using metasedimentary rocks as the source rocks indicates that felsic melts produced at ∼850 °C and 6−10 kbar can best match the target leucogranites in lithochemistry. In this regard, the anatectic temperatures previously obtained for the production of Himalayan leucogranites would probably be underestimated to some extent. Such high temperatures are difficult to explain purely by the internal heating of the thickened orogenic crust. Instead, they require an extra heat source, which would probably be provided by upwelling of asthenospheric mantle subsequent to thinning of the orogenic lithospheric mantle by foundering along the convergent plate boundary. Therefore, the Himalayan leucogranites of Miocene age would be derived from partial melting of the metasedimentary rocks in the post-collisional stage.

scholarly journals Assessment of the Environmental and Societal Impacts of the Category-3 Typhoon Hato

Atmosphere ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 296 ◽  
Author(s):  
Eric C. H. Chow ◽  
Min Wen ◽  
Lei Li ◽  
Marco Y. T. Leung ◽  
Paxson K. Y. Cheung ◽  
...  
Keyword(s):  
Hong Kong ◽  
High Temperature ◽  
Air Quality ◽  
Heat Index ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Temperature Record ◽  
Astronomical Tide ◽  
Extreme High Temperature

The destructiveness and potential hazards brought to the Pearl River Delta (PRD) by the category-3 typhoon Hato in 2017 have been studied. The results show that wind flow is one of the key parameters influenced by tropical cyclones. The observed wind at Shenzhen station changed from median southwesterly and calm northerly to strong easterly during the evolution of Hato as it approached the PRD and during landfall, respectively. The peak wind intensity at the surface level and a height of 300 m reached over 17 m s−1 and 30 m s−1, respectively. In Zhuhai, the area closest to the landfall location, the situ observation shows that the maximum wind and the maximum gust on 23 August 2017 reached 29.9 m s−1 and over 50 m s−1, respectively, which is a record-breaking intensity compared with the highest recorded intensity during tropical cyclone (TC) activity in Vicente in 2012. The maximum sea level during 23 August 2017, with an added influence from the storm surge and the astronomical tide, was found to be over 3.9 m to the west of Hong Kong. Extreme high temperature was also recorded on 22 August 2017 before the landfall, with 38.4, 38, and 36.9 °C of daily maximum temperature in Shenzhen, Macao, and Hong Kong, respectively. Based on the heat index calculated with the temperature record at Shenzhen’s station, the hot temperature hazard reached “danger” levels. On the other hand, a prominent air quality deterioration was observed on 21 August 2017. The concentrations rapidly increased to 1 time greater than those on the previous day in Hong Kong. The TC-induced sinking motion, continental advection, and less amount of cloud cover were observed before the landfall, and would be the possible factors causing the extreme high temperature and the poor air quality. This case study illustrates that the influences of Hato to the PRD were not only limited to their destructiveness during landfall, but also brought the extreme high temperature and poor air quality.

Materials—Metallic and Non-Metallic

1961 ◽  
Vol 65 (602) ◽  
pp. 83-85
Author(s):  
N. J. L. Megson
Keyword(s):  
High Temperature ◽  
Titanium Alloys ◽  
Aluminium Alloys ◽  
Elevated Temperatures ◽  
Maximum Temperature ◽  
Considerable Time ◽  
Heating Effects ◽  
Rain Erosion

With increasing speeds of aircraft, problems arise over materials of construction, partly through kinetic heating effects which cause temperature rises and partly through rain erosion effects. Additionally, account has to be taken of a required life of 30,000 hours which is much longer than that over which most materials are normally evaluated.For speeds of Mach 2.2, the maximum temperature attained will be of the order of 130°C, while for Mach 2.7 the corresponding temperature will be 200°C or higher. For the lower speed, it is probable that aluminium alloys will be satisfactory, although it must be emphasised that no information is yet available on the long-term behaviour of materials at the elevated temperatures likely to be experienced. Test programmes are in hand, but these will necessarily take considerable time for their completion. For speeds of Mach 2.7 or above, steel or titanium alloys will be required, but here again the necessary evaluation for long periods at high temperature has yet to be completed.

Summer infertility in pigs: its incidence and characteristics in an Australian commercial piggery

1978 ◽  
Vol 18 (94) ◽  
pp. 698 ◽  
Author(s):  
AM Paterson ◽  
I Barker ◽  
DR Lindsay
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Litter Size ◽  
Ovarian Function ◽  
Embryonic Mortality ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Fertilization Failure ◽  
Summer Temperatures

The records of five years' production in an 800 sow commercial piggery were examined and the relationships between summer temperatures, returns to service and litter size were considered. When mean daily maximum temperature exceeded 32�C during the week of service there was an increase in the number of sows failing to hold to service. The number of sows that returned to service 15-25 days after mating remained constant throughout the year, and summer infertility was characterized by an increase in the number of sows that exhibited extended, irregular return-to-service intervals. The litter size of sows that conceived during the period of summer infertility was not significantly different from that of sows conceiving at other times of the year. The data suggest that summer infertility is not due simply to fertilization failure, embryonic mortality or an increased incidence of abortions in sows mated during periods of high temperature. Neither does boar fertility appear to be in question. It seems most likely that heat stress around the time of mating may affect ovarian function, resulting in temporary infertility and an endocrine imbalance, which causes delayed, irregular returns to oestrus.

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